1. Field of the Invention
The invention relates to engine control systems and methods.
2. Background Discussion
Determining whether to start or stop an engine of an alternatively powered vehicle, such as a hybrid electric vehicle, may affect the fuel economy and undesirable exhaust gas emissions of the vehicle. Frequently starting and stopping the engine during heavy traffic conditions, for example, may decrease the vehicle's fuel economy and increase the vehicle's emissions.
Determining whether to start or stop an engine may be based on driver input. If, for example, the vehicle's accelerator pedal position exceeds a threshold, the engine may be started. Further, if the vehicle's brake pedal position exceeds a threshold, the engine may be stopped. In traffic conditions characterized by frequent vehicle starts and stops, determining whether to start or stop the engine based on driver input may result in frequent starting and stopping of the engine.
Determining whether to start or stop an engine may be based on a vehicle's speed. If, for example, the vehicle's speed is 5 miles per hour (mph) or faster, the engine may be started. Further, if the vehicle's speed is less than 5 mph, the engine may be stopped. In traffic conditions characterized by frequent vehicle starts and stops, determining whether to start or stop the engine based on speed may result in frequent starting and stopping of the engine.
An engine control system and method is desired that would regulate engine stop and start requests in real time to optimize engine performance based on an indicator of traffic conditions.